Ergonomic Weekly Presentation (Database Human Factor)

Anthropometric Principles in

Workspace and Equipment Design

Eris Elianddy Supeni, PhD

Introduction

• Anthropometry means measurement of the human body.

• Greek anthropos (man) and metron (measure)

Definition of Anthropometry

The part of anthropology (study of humans) having to do with measurements of the human body to determine differences in races, individuals, etc…

Source : Webster’s New 20th Century Dictionary (1970)

Definition of Anthropometry

The study of human body measurements esp. on a comparative basis.

Source: Merriam Webster’s Collegiate Dictionary (1993)

Definition of Anthropometry

Anthropometry is a science that deals with the measurement of size, weight, gender and proportions of the human body. It is empirical (experimentally derived) in nature and has developed quantitative methods to measure various physical dimensions. (Chaffin, 1984)

Occupational Ergonomics

Biomechanics

AnthropometryPsychology

Physiology

Industrial Engineering•Work Methods•Facility Layout

•Work Flow

MethodsAnalysis

WorkplaceDesign

Machine &Equipment

Design

ToolDesign

OperatorAssignments& Job Design

Anthropometric Data

• Used to specify dimensions of workspaces, equipment, furniture, clothing so as to ‘fit the task to the man’

• Avoid mismatches between the dimension of equipment, products to the user.

Why Anthropometric Data Important?

1. Optimize the dimensions of a diverse range of items. Example, length of toothbrushes, size of toolkits, size of clothes for Malaysian… others.

2. Good example is T-shirt size Large for Malaysians maybe size Small for New Zealand Rugby club.

Human Variability• Size

• Range of Motion

• Strength

• Endurance

• Stress tolerance

• Intelligence

• Dexterity

• etc.

The Story of Lacy and Andrew

Does one size fit all?Lacy is 4’ 10” (147 cm)

Andrew is 6’ 10” (208 cm)

Love conquers all – even anthropometry!

Where to get Anthropometric Data?

• Military?

• Hospital?

• Ministry of Health?

Basically there are problems because the way data obtained are not standard.

Meaning that Researcher A uses his method while Researcher B uses his own method.

5th and 95th Percentile

• Standard deviation, σ x 1.64 – MEAN = 5th percentile

• 1.64 + MEAN = 95th percentile.

• σ x 2.32 – MEAN = 1st percentile

• 2.32 + MEAN = 99th percentile

• Using these data, you can compute a range of statures, leg lengths and others.

Applying Statistics to Design

• Statistical information about body size is not directly applicable to a design problem.

• Designer has to analyze anthropometric mismatches and then decide the anthropometric data which is appropriate to the problem.

• A suitable percentile has to be chosen. • Example; a handicapped person in the

university. Current accommodation have been made for normal people. If a handicap person registers, he must adapt to the normal situation. Adjustments must be made by university to accommodate him.

Minimum Dimensions

• There are situations we need to use minimum dimensions for the comfort ability of most populations.

• The door way must be no lower than minimum value.

• Seat width must be no narrower than the largest hip width.

• In a female or mixed-sex workforce, the body width of a pregnant woman is used.

Maximum Dimensions

• A low percentile is chosen to determine the maximum height of a door latch so that the smallest adult in a population will be able to reach it.

• In public transport, the seat must be low enough so that a short person can rest the feet on the floor.

• The seat height must be no higher than 1st or 5th percentile.

Cost-Benefit Analysis

• Sometimes, not necessary to use anthropometric data in all cases.

• Often trade-offs between between the assitional costs of designing to suit a wide range of people and the number of people who will ultimately benefit.

Trade-off

• Example, the height of a car vs tall person.

• If Mean for sitting is 90 cm with standard deviation of 5cm, 50% driver can accommodate.

• Increase ceiling height to 100 cm (95+5+5), 84% can accommodate.

• Increase 5cm more i.e. 105cm will only accommodate extra 2% of the population.

• Also increase drag and friction.

• 5th and 95th percentile are often used to determine the dimensions of products.

Consequences of Mismatch

• Designer must predict the consequences of mismatch- how serious they can be and who would be affected.

• Example, the fire escape door. All people can handle it including children.

Mannequins

• Crash test dummies is created based on 5th and 95th percentile data.

• Expensive.

• Nowadays use software. Example

• www.sammiecad.com

Design for Everyone

• The problems of design that suits everyone can be solved by

1. Make different sizes

2. Design adjustable products

3. Anthropometry and Personal Space

Make different sizes

• Often heard of free-size shirts?

• Most people can wear it.

• The size is based on minimum dimensions of the population.

• How about people who wanted size S, M, L, XL, XXL, XXXL?

• Designers must make shirts with different sizes for different races/countries.

Design Adjustable Products

• Design the mechanism that can adjust with the ease of operation.

Anthropometry and Personal Space

• Everyone have personal space.

• Regard as an area of space that are preserved.

• In the workplace, a minimum separation of desks or benches of approximately 1.2 meters is necessary.

Summary

• 5th and 95th percentile plays big role in determining the minimum value of dimensions of products.

• Trade-off is unavoidable in designing products.

• Use of mannequin is good for testing.

• Design for everyone can be approached in several ways.

The End

Assignments

• In this task you will gather anthropometric data of your friends.

• From the data, you will plot a normal distribution graph.

• In order to get the graph, you must get the standard deviation and MEAN.

• Each group must get data from 20 people

• Take pictures of each measurement taken. (You do not need to take picture of everyone)